| Latimeriidae (Gombessa) |
| 168 cm TL (male/unsexed); 200 cm TL (female); max.weight: 95 kg; max. reported age: 48 years |
|
demersal; marine; depth range 150 - 700 m, non-migratory |
| Indian Ocean: well known population off the islands of Grand Comoro and Anjouan in the Comoros. Other populations in South Africa (Ref. 11228, 38218), Madagascar (Ref. 26162), and Mozambique (Ref. 27415). Likely to occur as strays at islands like Astove and Cosmoledo (Ref. 1623). |
|
Dorsal spines (total): 8-8; Dorsal soft rays (total): 30-31; Anal spines: 0-0; Anal soft rays: 27-31. This species have the following characters: D VIII+30-31; A 27-31; P 29-32; V 29-33; C 20-25/35-38/21-22; LL 94-104; gills 4; gill rakers replaced by spiny tooth-plates. Head naked, the opercular bones exposed; gill cover expanded posteriorly and ventrally as a thick flap of skin; lower jaw with two large, overlapping gular plates; teeth conical, set on bony plates attached to palatines, ectopterygoids, and dentaries; maxilla absent (the structure at the side of the upper jaw that appears to be a maxillary bone is a thick fold of skin connecting the upper jaw to the rear of the lower jaw). Swim bladder elongate, filled with fat; intestine with spiral valve; osmoregulation involves retention of urea and trimethylamine oxide in the blood, but urea is not resorbed by the kidneys and excess salts are excreted by the rectal gland. In adults the brain is incredibly small, occupying only about 1% of the cranial cavity; but in the smallest juveniles, the brain completely fills the cranial cavity. Color in life: dark metallic blue, the head and body covered with irregular white or pale bluish spots. After death, the bluish color fades to dark brownish black. |
| Known as the living fossil. Inhabits steep rocky shores, sheltering in caves during the day (Ref. 38425), with as much as 14 individuals in a single cave (Ref. 38426). Foraging singly over open substrate at night (Ref. 38426), it drifts passively with the current or swims slowly with its paired fins and its second dorsal and anal fins (Ref. 38427). May travel as much as 8 km at night searching for food and retreats to the nearest cave before dawn (Ref. 38426). Preys on fishes and squid (Ref. 26162). Beryx, Polymixia, Symphysanodon, apogonids, a skate, an eel and a swell shark have been known to be eaten (Ref. 11228). Its main enemies are likely to be large sharks (Ref. 26162). Ovoviviparous, with as much as 5-29 young (Ref. 11228, 37171). Gestation period estimated at 3 years, which would be the longest known in vertebrates (Ref. 30865). A small relative gill area (Ref. 38428) restricts coelacanths to a life 'in the slow lane', drift-feeding at night in cold waters and resting in slightly warmer caves for food consumption during day time (Ref. 38429). Recently, Prof Hans Fricke and associates have succeeded in observing and filming Latimeria in their natural habitat. Using a two-man submersible, Fricke found several coelacanths in depths of 120-400 m on the barren lava slopes off Grand Comoro. Coelacanths have distinctive white markings, and this allowed recognition of individuals and tracking of their movements. During the day, Latimeria retreat to caves, with as many as 13 fish crowded together in a single cave. Several individuals occupy overlapping home ranges, and Fricke never saw any aggressive encounters between coelacanths. By resting in caves (were there are no strong currents) the coelacanths save energy and avoid encounters with large predators (deep-water sharks). After sunset, the coelacanths leave their caves and drift slowly across the substrate, presumably looking for food, within 1-3 meters of the bottom. On these nightly hunting forays, the coelacanth may travel as much as 8 km; and before dawn they shelter in the nearest cave. While searching for prey, or moving from one cave to another, Latimeria appears to move in slow motion, either drifting passively with the current and using its flexible pectoral and pelvic fins to adjust its position, or slowly swimming by a synchronous sculling movement of the second dorsal and anal fins. In slow forward swimming, the left pectoral and right pelvic fins move forward, while the right pectoral and left pelvic fins are pulled backward. This tandem movement of alternate paired fins resembles the movement of the forelimbs and hindlimbs of a tetrapod walking on land. Latimeria does not use its lobed fins for walking on the bottom, and even when they are resting in caves they usually do not touch the substrate. Like most slow moving fishes, the coelacanth can make a sudden lunge or fast start by means of a quick flip of its massive caudal fin. During its nightly foraging swims, Latimeria was often seen to perform head-stands, in which it rotates its body into a vertical position, with its head near the bottom and its caudal fin curved perpendicular to its body. It then held this position for two or three minutes at a time. This curious behavior may be used when it is scanning the bottom with its putative electoreceptive rostral organ, or it may be a reaction to the bright lights of Prof. Fricke's submersible (Ref. 38228). |
|
Critically Endangered (CR); Date assessed: 30 June 2000 (A2bcd) Ref. (130435)
|
| harmless |
|
Occurrence in South Africa is based on a specimen (long thought to be a stray) taken off the Chalumna River at a depth of 70 m on 21 December 1938 and preserved as a mounted specimen in the East London Museum. Also on the sighting of a juvenile (1 m) and an adult (1.6 - 1.8 m) in Sodwana Bay, northeast coast.
Although only a single specimen of the coelacanth has been caught off South Africa, the discovery of this specimen did much to put South Africa and J.L.B. Smith on the ichthyological map of the world. Thanks to the efforts of J.L.B. and Margaret Smith, French anatomists, and more recently, Hans Fricke's observations and films of coelacanths in their natural habitat at Grand Comoro Island, we have learned much about this fascinating fish. A brief history of the discovery of the first and second specimens known to science is given below, followed by a summary of what is known about the biology and ecology of the coelacanth. The detailed account of the astonishing discovery of the first living coelacanth and J.L.B. Smith's search for the home of Latimeria is told in his book Old Fourlegs: The Story of the Coelacanth (Longmans, Green & Co., London, 1956; 260 pp).
Heading for East London on 21 December 1938, the Irvin & Johnson trawler Nerine made a last haul in a depth of about 70 m off the Chalumna River. The catch included an assortment of sharks and a large blue fish with a peculiar tail. Captain Hendrik Goosen often saved anything unusual from his catches for Majorie Courtenay-Latimer, the young curator of the East London Museum; and the extraordinary blue fish was left with some sharks at the harbour for Miss Latimer. The next morning, Miss Latimer was notified that the Nerine had docked with some specimens for her. Sorting through the pile of sharks, rays, etc., she found "the most beautiful fish I had ever seen ... It was 5 feet long and a pale mauvy blue with irridescent silver markings." She resolved to take the fish to the museum, and with the help of her assistant, they carried it in a bag to the taxi. The taxi driver objected "No stinking fish in my taxi!" Miss Latimer replied, "Well you can go, the fish is not stinking -- I will call another taxi." With that, he allowed them to put it in the boot of the taxi. The fish was preserved as a mounted specimen, because there was no suitable preserving tank or freezer at the museum. Frustrated in her attempts to identify the fish, Miss Latimer sought the assistance of Dr J.L.B. Smith, who was then a lecturer in chemistry at Rhodes University in Grahamstown. Smith was also a self-taught ichthyologist and had already published several papers on the marine fishes of South Africa. The strange blue fish was recognised as a coelacanth by Smith, and his publication of the description of this "living fossil" (which he named Latimeria chalumnae in honour of Miss Courtenay-Latimer and the river near where it was caught) astounded the international zoological community.
Unfortunately, the internal organs of the fish were discarded by the taxidermist before the value of this unique fish was realised; consequently, it was of great importance to find a second, intact specimen. By the late 1940s, there was little doubt that the East London coelacanth was a stray; and J.L.B. Smith deduced that the home of the coelacanth was to the north, in the Mozambique Channel. A poster depicting a coelacanth and offering a reward of £100 (hence the "hundred-pound-fish") resulted in one caught in December of 1952 at the Comoro Islands being given to Captain Eric Hunt. News of this second coelacanth was telegraphed to J.L.B. Smith, who, fearing that it might not be properly preserved, contacted the South African Prime Minister, Dr D.F. Malan, for assistance in the speedy retrieval of the specimen. Dr Malan understood the value to science of this second known coelacanth, and he arranged for an Air Force plane to take Professor Smith to the Comoros to fetch the fish. J.L.B. Smith was greatly relieved to see that Eric Hunt had identified the coelacanth correctly and that it was adequately preserved.
Since 1952, more than 170 coelacanths have been caught with hook and line in depths of 100 - 400 m on the steep volcanic slopes of Grand Comoro and Anjouan. The natives were familiar with the fish, which they called "gombessa"; but they did not eat it and had no use for it. The local fishermen would catch two or three per year while fishing for oilfish (Ruvettus pretiosus) at night from canoes.
The coelacanth feeds on small deep-reef fishes. Beryx, Polymixia, Symphysanodon, apogonids, a skate, an eel, and a swell shark have been found in its stomach. Judging from its sluggish lifestyle and the small surface area of its gills, the coelacanth has a low metabolic rate and, consequently, its food (energy) requirements are relatively low for such a big fish. This low-energy lifestyle is an advantage on the relatively barren volcanic slopes and specialised habitat of the coelacanth where food is scarce. |
Source and more info: www.fishbase.org. For personal, classroom, and other internal use only. Not for publication.
